Measure post-blood meal dispersal of mosquitoes and duration of radioactivity by using the isotope 32P

The radioactive isotope 32P-labeled disodium phosphate (Na2H32PO4) was injected into a cow via the jugular vein kept in a shed in Maozhuang Village, Cao Township of Shanxian County China. Over the following 5 days, mosquitoes feeding on the cow were captured at distances up to 400 m to determine dispersal distance. Duration of radioactivity in the cow and marked mosquitoes were for 10 days. The results showed that after blood-feeding, An. sinensis and Cx. tritaeniorhynchus temporarily rested in the cattle shed and then flew outdoors. In contrast, Cx. pipiens pallens remained in the cattle shed after feeding. These findings confirmed that local An. sinensis and Cx. tritaeniorhynchus were partially endophilic and tended to rest out of doors, whereas Cx. pipiens pallens endophilic. For marked An. sinensis and Cx. tritaeniorhynchus, there was a significant tendency for dispersal to be in a northeast and east direction, probably because of the presence of heavy shading by agricultural field, a small river for mosquito oviposition places and downwind from the blood source. The furthest flight distances for An. sinensis and Cx. tritaeniorhynchus were 210 and 240 meters, therefore, control of these mosquitoes should include resting places indoors and outdoors within a radius of 250 m from confirmed cases.